Kyrees Sullivan, 16, and 15-year-old Harvey Evans were riding an electric bike when the collision occurred.

CCTV footage showed the pair being followed by a police van moments before the fatal crash on Snowdon Road in Ely.

Harvey's family said their son was "fun and loving" and "not as the media are portraying him now" and called for peace in the community after the collision sparked riots earlier this week.

In a tetchy press conference, Deputy Chief Constable Rachel Bacon said South Wales police and crime commissioner Alun Michael had been correct to say that no police vehicles were involved in the collision.

DCC Bacon laid out a timeline of the case, and reiterated the police's statement that "there was no police vehicle on Snowden Road at the time of the collision. And we believe there were no other vehicles involved in the incident."

However, in the timeline of events she did admit that a police van had been following the bike less than two minutes before the fatal crash.

She added that there was "no excuse" for the violence which erupted in Ely following the incident and appealed for more information to aid officers in the investigation, both into the crash and the riot.

"It didn't go as any of us would have wanted on the night of the incident," she said. "It is a tragic outcome that two young men have died and we want to understand why."

Earlier, the families of both of the teenagers paid tribute to them.

Harvey's family said their hearts were "truly broken" by his death and described him as living "life to the full" and having a "big heart" adding that "deep down, he truly cared".

The family also said they asked for "peace within the community and request that people leave the investigation to the police so we can get the answers we so desperately need.

"As Harvey's mum I want to remember our son as the fun and loving son that he was and not as the media are portraying him now".

Kyrees's family described him as a "handsome young man" and a "loving son and brother" adding that he and Harvey "went everywhere together" and were loved "not only by their families but by their community as well".

It comes as flowers have been laid in tribute to the boys - while the police watchdog has confirmed it will investigate the incident.

Messages of tributes near the crash site included "Rip Ki and Harvey" along with pictures of the two boys.

CCTV footage obtained by Sky News on Tuesday appeared to show two people on a bike being followed by a police vehicle in Frank Road at 5.59pm, just under a mile from the crash site.

South Wales Police has denied any of its officers were at the site of the crash when it occurred.

The police watchdog has said it will probe "any interaction" between South Wales Police officers and two boys before they were killed.

Ely resident Leanne Morkot told Sky News she saw a police van following two people on a bike as she walked to her local shop.

"Bike's come round, two people on a bike and seconds later, van's coming round the corner on the opposite side of the road," she said.

The shop is around half a mile from Frank Road.

Police continue to appeal to members of the public for further evidence that can help piece together events leading up to the crash.

Riotous scenes followed the collision with cars set alight and properties damaged.

One man's taxi had its window smashed in Stanway Road as rioters moved down the street towards Highmead Road.

Officers remained at the scene to respond to the unfolding situation until the early hours of Tuesday.

South Wales Police said 15 officers were injured during the riots and 11 of them were taken to hospital for treatment.

Jenny Sampson, Harvey's godmother, told Sky News the police would not let the boys' parents through to see them after the collision and said it was "disgusting" how they were treated.

The force said it had made a mandatory referral to the Independent Office for Police Conduct (IOPC).

The police watchdog confirmed on Wednesday it will investigate the circumstances surrounding the incident.

Read more:
Residents describe 'horrible' chaos after teenagers died in crash
Two boys killed in Cardiff crash which was followed by riot are named

The IOPC said in a statement: "Following a referral from South Wales Police we have decided to independently investigate an incident in Ely, Cardiff, on Monday which resulted in the deaths of two teenagers.

"Our decision to investigate follows our attendance at the police post-incident procedure and after a review of the information received to date.

"We will be examining any interaction between the police and the boys after CCTV footage emerged apparently showing a police vehicle following a bike prior to the incident."

In another statement released later on Wednesday, IOPC Director for Wales David Ford said: "We are not the police and our investigations are independent of the police.

"Our role is now to speak to members of the community and gather evidence, including CCTV and witness statements, to understand the circumstances leading up to the collision.

"This incident has had a profound impact on the local community and it is vitally important that the facts are established through a thorough and impartial investigation.

"Our investigative and community engagement work in the local area will continue for some time to come. Further updates will be provided as our investigation progresses.

"Upon conclusion of the investigation we will determine whether there is any indication that anyone serving with the police may have breached the standards of professional behaviour."

A vigil and balloon release is being planned as part of a tribute to the boys.

A post on Facebook said the vigil would take place at 6pm on Friday in Snowden Road, where the crash happened.

The post asked those attending to bring blue balloons.

First Minister Mark Drakeford, who is also the local Senedd member, said his thoughts were "with the families of the two young people who died".